Rotary boring-drill



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5 I I I mcjfugfges, mmim H. HUGHES. ROT some DRILL.

APPLICA FILED MAY 19, I919.

1 327, 9 13. Patented Jan. 13, 1920.

mum!!! HOWARDYR. HUGHES, or nous'ron, 'rnxns.

ROTARY BORING-DRILL.

To all whom it may concern:

.Be it known that I, HOWARD R. HUGHES, a citizen of the United States,residing at Houston, Harris county, Texas, have invented a certain newanduseful Improvement in Rotary Boring-Drills, of'which the following isa full, clear, and exact description,

such as Will enable others skilled in the art v to which it appertainsto make and'use. the

same.

My invention relates to an improvement in rotary boring drills for usein drilling earth or rock in oil, water, or as wells, or the like. Ithas special app ication to earth boring drills of the roller type, inwhich the cutting or drilling operation is performed by means ofrotarycutters adapted -to roll upon the bottom of the hole and disintegratethe material which is adaptedto be flushed away by means of streams ofwater forced downwardly through the hollow drill stem and the head ofthe bit. This particular form of roller bit is called the ,cross rollertype from the fact that it has twoiside cutters for drilling the outerperiphery of the hole and a central cross roller for cutting the centerof the bottom of the hole.

' breakingor mutilation thereof. Other ob-' jects and advantages willmore clearly ap-- An object of my invention is to provide a pear in thedescription which follows.

1 Referring to the drawings forming apart of this specification, and inwhich like characters of reference are applied to like parts throughoutthe several views, Figure 1 is a side view partlyin elevation and partlyin central longitudinal section showing the preferred form of myinvention; Fig. 2 is a similar view taken at right angles to the viewshown in Fig. 1; Fig. 3 is a bottom plan view of the preferredembodlment; and Fig. 4 is abrokenview of the head of my improved tool,showing a modified mountin of the cross roller cutters.

ily invention is an improvement on the Specification of Letters Patent.

Patented Jan. 13, 1920.

Application filed May 19, 1919. Serial No. 297,979.

type of bit shown in my revious Patent No. 1,174,576, patented Marc 7,1916. It comprises an approximately cylindrical shaped head 1, having anupper threaded shank 2 for attachment to a rotary drill stem, not

shown. At the 'upper end of the shank 2 is va threaded nipple 3 .ofsmall diameter to which a 'lubricant container is adapted to beattached. The lower face of the head is provided with an approximatelyV-shaped slot 4 to provide a housing for two sets of cross rollercutters 5. These cutters are mounted upon shafts 6 supported at thecenter of the bit in a transverse web 7. This web not only furnishes asupport for the cutter shafts but also provides a reinforcing meanstransversely ofthe V-shaped slot 4 to materially strengthen the head ofthe b1t. This web is an important feature .of

my invention, as will more clearly appear.v

The outer ends of the cutter shafts 6 are supported in downwardlyprojecting arms 8' from the head, these arms serving to partially closethe end of the V-shaped slots 4, in which the cutters are mounted. Thecutter shafts 6 are of large diameter at the outer end to accommodate-acutter 5 of slightly larger diameter than the other cross rollercutters, and is reduced somewhat in diameter toward the center of thehead to accommodate a plurality of somewhat smaller cutters 5 The'shaftin my 1m- 7 proved embodiment is inclined somewhat upwardly toward thecenter of the head and is still further reduced in diameter at 9 andthreaded for engagement with the central web 7 of the head. The shaft isretained in position partly by the threaded engagement 9 and a so bymeans of a locking pin 10 at the outer end of the shaft, this pin beingset in the side of the supporting member 8 at right angles to the shaftand fitting within an annular groove 11' in-the periph, cry of theshaft. It will be noted that the threading pf the shaft 6 intoengagement with the central web 7 not only assists in retaining theshaft in position but also materially strengthens the head by preventingany tendency of the outer support 8j to'be spread outwardly by the forceof the cfuttin action.

The cutter shaft for the cross'ro ers may be horizontal instead ofinclined upwardly, as shown in Figs. 2 and 3,'and

obtain astill further strengthening of the head. This form of cuttershaft is shown in Fig. 4. The shaft 6 is mounted at each end in thesupporting arm 8 and is; further supported at its central point in thecentral web 7, as described in the previous modification. The cuttersused in this modification are identical with those shown in Fig. 2.

The side cutters 12 are mounted on the sides ,of the head at the lowerend thereof. These cutters are disk-shaped, having an outer cylindricalcutting periphery 13 with the outer edge of the cutting face beveled toprovide cutting teeth 14 in such position as to act 'upon the side ofthe hole being drilled. The inner edge of the cutting disk is alsotoothed, as shown at 15, to accommodate a slightcutting action towardthe center of the bit. These two side cutters are mounted upon pins 16which are made integral with the outer side walls 17 of the V- shapedhousing at the lower end of the head. Said pins 16 are threaded and arereduced in diameter at the outer end at 18 to accommodate a locking nut19.

Threaded upon the pins 16 are bushings 20, these bushings being slightlyfrustoconical on their outer periphery, as shown in'Fig. 1 The cutters12 are provided with a frusto-conical inner bearing surface 21 adaptedto fit against the bushing 20. The inner faces of the cutters 12 bearagainst anti-friction washers 22 of ordinary construction. It will benoted that in assembling this cutter the bushing 20 will be insertedwithin the cutter and in this position will be threaded upon the cutterpin 16. The locking nut 19 will then be threaded upon the cutter end 18of the pin, thereby serving to prevent the removal of the bushing andcutter. This form of mounting for the cutter is especially adapted forthe purpose, in that the upward and outward thrust of the cutting actionwill be received against the frusto-conical surface of the bushin insuch manner as to most efiiclently wit stand the pressure and to providea bearing surface such that the cutterwill be freely rotatable at alltimes. The side cutters 12 are so mounted as togive as free rotationthereof as possible, and\for this reason are not housed in the head butare left as open as possible on the sides for free drilling action, thehead being recessed slightly at 23 to allow for the inward inclinationof the cutters necessary in this form of bit.

The cutters are lubricated by means of lubricant passing downward fromthe lubricant container through the central channel 24. This channel hastwo laterally branch ing ducts 25 leading to the center of the cuttershafts 16 and through lateral ducts 26 to the bearing surface between'the cutter and the bushing. The central channel 24: leads downwardlythrough the central web 7 to the shaft 6, and through central ducts 27therein to the bearing surfaces ofthe cutters.

Flushing water for carrying away the material disintegrated by the bitis supplied through vertical channels 28 leading from the upper shank ofthe bit downwardly to the V-shaped recesses 4. These channels are 4 innumber, as shown particularly. in Fig. 3, there being 2 ,of thesechannels in the housing at each side of the transverse web 7. A largesupply of the flushing water is thereby obtained so that the bottom ofthe hole is washed constantly clean-of cuttings, it being therebyunnecessary to supply flushing water directly upon the side cutters 12.

This form of bit is particularly strong in construction due to themanner in which the cutters are mounted in the head. The strengtheningof the two side 'walls 17 by means of a transverse Web prevents anyspreading of the lower faces upon which the cutters are mounted and alsoprovides a central support for the cross roller. The forming of theside-cutter pins 16 integral with the head gives an especially strongsup port, and the frusto-conical bushing 20 very effectively takes up.the thrust ofthe cutting action of these cutters. Cutters 5 upon thecross roller shaft 6 are stepped downwardly toward the center of the bitso as to drill a hole with aslightly convex or conical shaped bottom.This will act to prevent a too pronounced whipping or wabbling action ofthe bit in the hole and will serve to center the bit so that a straighthole may be more readily drilled.

It also allows for a strengthening of the walls 17, upon which thesidecutters 12 are mounted, by making it possible to thicken the wallstoward the center of the bit where the cutters are of smaller diameter.The purpose of centering the bit in the hole is further served in thepreferred embodiment ofmy bit by inclining the cutter shafts 6 slightlyupwardly toward the center. This the cutter is mounted. It is obviousthat if it'were necessary to extend the wall of the head downwardly tosupport the outer end of the cutter pin 16, so as to provide a slot orhousing for the outer cutter, it would also be necessary that the outercutter be of decreasedithickness, and that it also be set fartherinwardly toward the center of the head so that the supporting wall atthe outer face might extend downwardly to enwill be obvious, what Iclaim as new and.

desire to'protect by Letters Patent iszi '1. In a rotary boring drill, ahead, two sets of cylindrical cross roller cutters so'positioned as todrill a hole. with a conical shaped bottom, two side cutters mounted onpins projecting outwardly from the sides of the head, said cutters beingretained in position by frusto-conical shaped bushings threaded .on pinsintegral with said head,

and locking means to hold said bushings on.

said pins. r

2. In a rotary boring drill, a head, two sets of cross roller cuttersthereon, two laterally projecting pins integral with the sides of saidhead, frusto-conical bushings threaded on said pins, the larger ends ofsaid bushings being toward the outer ends of said pins, and cuttersmounted on said v bushings and retained in position thereby.

3. In a rotary boring drill, a head, an'

approximately V -shaped housing in the lower end thereof, a transverseweb midway of said housing adapted to divide said housing into twochambers to. strengthen the walls of said housing, inclined cuttershafts in said chamber supportedat one end in said web, cylindricalcutters on said shafts, the cutters being of unequal diameter andarranged with the smaller cutters at the cjenter of the head, twoopposite cutters on the,

outer face of the head and means to discharge fius hing water into saidhousin In testimony whereof, I hereunto a signature this the 15th day ofMay, A. D.

' HOWARD HUGHES.

